The present invention pertains to a pneumatic tire for motor vehicles with running surface profile designed in the direction of rotation, with two shoulder regions each being a constituent of a row of shoulder blocks, and with a middle region separated from them by circumferential grooves running in the circumferential direction; this middle region encompasses the width of the circumferential grooves and covers a minimum width of 65% of the width of the running surface, is free from circumferential grooves running in the circumferential direction and is equipped with a number of V-shaped running grooves, which open into the circumferential grooves and whose V-peaks rest at least essentially on the equator line.
A pneumatic tire for motor vehicles with a running surface designed in this manner is known, for example, from EP-A1-0 788 898. In the middle region of the running surface the rills running at a V-shape in a sequence in the circumferential direction are alternately joined left and right of the equator line by grooves aligned opposite to their profile. Together with additional, comparatively narrow grooves which each are located halfway between the V-peaks of the rills and the outer, circumferential grooves, there is an arrangement of the middle region into profiled positives.
A running surface profile which has no circumferential grooves going all the way around in the circumferential direction, is known from DE-A1-38 34 383. The profile rills are arranged so that a rotation-based running surface is produced which consists of a number of slant-oriented profile positives running at an acute angle to the equator line. The profile positives and the rills in one half of the running surface are directed opposite to those in the other half of the running surface. A particularly good drainage capability is to be achieved by this configuration.
The running surface profile known from DE-A1-39 42 043 has a similar configuration. Transverse cuts of small width are provided parallel to the profile positives and profile rills, emanating from the shoulder regions. These cuts are intended to improve the wet slip resistance and the noise level of the running surface profile.
In these variants of rotation-based running surface profiles known from the state of the art, the primary objective is to achieve a good drainage capacity in order to prevent the occurrence of aqua-planing. The proposed measures do indeed provide a certain contribution toward this end, however, they cannot satisfy the ever-increasing requirements.
Accordingly, it is an object of the present invention to improve the water-diverting properties of a pneumatic tire for motor vehicles of the kind described above, so that even under unfavorable conditions and at the fastest possible driving speed, the occurrence of aqua-planing will be prevented. In this regard, the additional tire or profile properties, whether it be the generation of noise, the wear on the running surface, handling and comfort, can be kept to a high level.
The above and other objects of the present invention can be achieved in a tire that has in the two partial regions of the middle region running to the side of the equator line of the tire a number of slanting grooves which are oriented in the same direction to the profile of the V-shaped grooves, crossing at least three V-shaped grooves following each other in the circumferential direction and being at least essentially of a straight design. In the tire of this invention, these slanting grooves run at an incline to the equator line of the tire with a much smaller angle than the V-shaped grooves and which are the widest of all grooves or rills of the profile. As a result the slanting grooves of the one partial region of the middle region are offset in the circumferential direction with respect to those of the other partial region.
The combination of rills running in a V-shape with wide slanting grooves running in the same direction as the V-shaped rills but much steeper to the circumferential direction, has proven to be particularly advantageous for a definitive improvement in the water shunting capacity. The slanting grooves jointly with the rills running in a V-shape, form a number of channels which force the water to the side. Thus, the collection of water in front of the tire often observed for the circumferential grooves and which causes the aqua-planing is prevented.